To study water and electrolyte distributions and alterations in normal animals and in those with hemorrhagic or septic shock, tracer studies include administration of tritiated water and labeled sucrose. After equilibrium, an osmolal load is given I.V. to measure the osmotic volumes of dilution compared to the isotope dilution volumes. Computer analysis of the early arterial disappearance curves of isotopic tracers is used to predict the final volumes. BIBLIOGRAPHIC REFERENCES: Postel, J., Furtado, D., and Schloerb, P.R. Physiologic response to bacteremia. Fed. Proc. 34:380, 1975. Schloerb, P.R., Postel, J., Moritz, E.D., and Dolginow, Y.D. Hypothermic storage of the dog kidney for 48 hours with a low-chloride solution. Surg., Gynec. & Obstet. 141:545-548, 1975.